<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Queue
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Db.php 18705 2009-10-26 13:05:13Z matthew $
 */

/**
 * @see Zend_Queue_Adapter_AdapterAbstract
 */
require_once 'Zend/Queue/Adapter/AdapterAbstract.php';

/**
 * @see Zend_Db_Select
 */
require_once 'Zend/Db/Select.php';

/**
 * @see Zend_Db
 */
require_once 'Zend/Db.php';

/**
 * @see Zend_Queue_Adapter_Db_Queue
 */
require_once 'Zend/Queue/Adapter/Db/Queue.php';

/**
 * @see Zend_Queue_Adapter_Db_Message
 */
require_once 'Zend/Queue/Adapter/Db/Message.php';

/**
 * Class for using connecting to a Zend_Db-based queuing system
 *
 * @category   Zend
 * @package    Zend_Queue
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Queue_Adapter_Db extends Zend_Queue_Adapter_AdapterAbstract
{
	/**
	 * @var Zend_Queue_Adapter_Db_Queue
	 */
	protected $_queueTable = null;

	/**
	 * @var Zend_Queue_Adapter_Db_Message
	 */
	protected $_messageTable = null;

	/**
	 * @var Zend_Db_Table_Row_Abstract
	 */
	protected $_messageRow = null;

	/**
	 * Constructor
	 *
	 * @param  array|Zend_Config $options
	 * @param  Zend_Queue|null $queue
	 * @return void
	 */
	public function __construct($options, Zend_Queue $queue = null)
	{
		parent::__construct($options, $queue);

		if (!isset($this->_options['options'][Zend_Db_Select::FOR_UPDATE])) {
			// turn off auto update by default
			$this->_options['options'][Zend_Db_Select::FOR_UPDATE] = false;
		}

		if (!is_bool($this->_options['options'][Zend_Db_Select::FOR_UPDATE])) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception('Options array item: Zend_Db_Select::FOR_UPDATE must be boolean');
		}

		if (isset($this->_options['dbAdapter'])
		&& $this->_options['dbAdapter'] instanceof Zend_Db_Adapter_Abstract) {
			$db = $this->_options['dbAdapter'];
		} else {
			$db = $this->_initDbAdapter();
		}

		$this->_queueTable = new Zend_Queue_Adapter_Db_Queue(array(
            'db' => $db,
		));

		$this->_messageTable = new Zend_Queue_Adapter_Db_Message(array(
            'db' => $db,
		));

	}

	/**
	 * Initialize Db adapter using 'driverOptions' section of the _options array
	 *
	 * Throws an exception if the adapter cannot connect to DB.
	 *
	 * @return Zend_Db_Adapter_Abstract
	 * @throws Zend_Queue_Exception
	 */
	protected function _initDbAdapter()
	{
		$options = &$this->_options['driverOptions'];
		if (!array_key_exists('type', $options)) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception("Configuration array must have a key for 'type' for the database type to use");
		}

		if (!array_key_exists('host', $options)) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception("Configuration array must have a key for 'host' for the host to use");
		}

		if (!array_key_exists('username', $options)) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception("Configuration array must have a key for 'username' for the username to use");
		}

		if (!array_key_exists('password', $options)) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception("Configuration array must have a key for 'password' for the password to use");
		}

		if (!array_key_exists('dbname', $options)) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception("Configuration array must have a key for 'dbname' for the database to use");
		}

		$type = $options['type'];
		unset($options['type']);

		try {
			$db = Zend_Db::factory($type, $options);
		} catch (Zend_Db_Exception $e) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception('Error connecting to database: ' . $e->getMessage(), $e->getCode());
		}

		return $db;
	}

	/********************************************************************
	 * Queue management functions
	 *********************************************************************/

	/**
	 * Does a queue already exist?
	 *
	 * Throws an exception if the adapter cannot determine if a queue exists.
	 * use isSupported('isExists') to determine if an adapter can test for
	 * queue existance.
	 *
	 * @param  string $name
	 * @return boolean
	 * @throws Zend_Queue_Exception
	 */
	public function isExists($name)
	{
		$id = 0;

		try {
			$id = $this->getQueueId($name);
		} catch (Zend_Queue_Exception $e) {
			return false;
		}

		return ($id > 0);
	}

	/**
	 * Create a new queue
	 *
	 * Visibility timeout is how long a message is left in the queue "invisible"
	 * to other readers.  If the message is acknowleged (deleted) before the
	 * timeout, then the message is deleted.  However, if the timeout expires
	 * then the message will be made available to other queue readers.
	 *
	 * @param  string  $name    queue name
	 * @param  integer $timeout default visibility timeout
	 * @return boolean
	 * @throws Zend_Queue_Exception - database error
	 */
	public function create($name, $timeout = null)
	{
		if ($this->isExists($name)) {
			return false;
		}

		$queue = $this->_queueTable->createRow();
		$queue->queue_name = $name;
		$queue->timeout    = ($timeout === null) ? self::CREATE_TIMEOUT_DEFAULT : (int)$timeout;

		try {
			if ($queue->save()) {
				return true;
			}
		} catch (Exception $e) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception($e->getMessage(), $e->getCode());
		}

		return false;
	}

	/**
	 * Delete a queue and all of it's messages
	 *
	 * Returns false if the queue is not found, true if the queue exists
	 *
	 * @param  string  $name queue name
	 * @return boolean
	 * @throws Zend_Queue_Exception - database error
	 */
	public function delete($name)
	{
		$id = $this->getQueueId($name); // get primary key

		// if the queue does not exist then it must already be deleted.
		$list = $this->_queueTable->find($id);
		if (count($list) === 0) {
			return false;
		}
		$queue = $list->current();

		if ($queue instanceof Zend_Db_Table_Row_Abstract) {
			try {
				$queue->delete();
			} catch (Exception $e) {
				require_once 'Zend/Queue/Exception.php';
				throw new Zend_Queue_Exception($e->getMessage(), $e->getCode());
			}
		}

		if (array_key_exists($name, $this->_queues)) {
			unset($this->_queues[$name]);
		}

		return true;
	}

	/*
	 * Get an array of all available queues
	 *
	 * Not all adapters support getQueues(), use isSupported('getQueues')
	 * to determine if the adapter supports this feature.
	 *
	 * @return array
	 * @throws Zend_Queue_Exception - database error
	 */
	public function getQueues()
	{
		$query = $this->_queueTable->select();
		$query->from($this->_queueTable, array('queue_id', 'queue_name'));

		$this->_queues = array();
		foreach ($this->_queueTable->fetchAll($query) as $queue) {
			$this->_queues[$queue->queue_name] = (int)$queue->queue_id;
		}

		$list = array_keys($this->_queues);

		return $list;
	}

	/**
	 * Return the approximate number of messages in the queue
	 *
	 * @param  Zend_Queue $queue
	 * @return integer
	 * @throws Zend_Queue_Exception
	 */
	public function count(Zend_Queue $queue = null)
	{
		if ($queue === null) {
			$queue = $this->_queue;
		}

		$info  = $this->_messageTable->info();
		$db    = $this->_messageTable->getAdapter();
		$query = $db->select();
		$query->from($info['name'], array(new Zend_Db_Expr('COUNT(1)')))
		->where('queue_id=?', $this->getQueueId($queue->getName()));

		// return count results
		return (int) $db->fetchOne($query);
	}

	/********************************************************************
	 * Messsage management functions
	 *********************************************************************/

	/**
	 * Send a message to the queue
	 *
	 * @param  string     $message Message to send to the active queue
	 * @param  Zend_Queue $queue
	 * @return Zend_Queue_Message
	 * @throws Zend_Queue_Exception - database error
	 */
	public function send($message, Zend_Queue $queue = null)
	{
		if ($this->_messageRow === null) {
			$this->_messageRow = $this->_messageTable->createRow();
		}

		if ($queue === null) {
			$queue = $this->_queue;
		}

		if (is_scalar($message)) {
			$message = (string) $message;
		}
		if (is_string($message)) {
			$message = trim($message);
		}

		if (!$this->isExists($queue->getName())) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception('Queue does not exist:' . $queue->getName());
		}

		$msg           = clone $this->_messageRow;
		$msg->queue_id = $this->getQueueId($queue->getName());
		$msg->created  = time();
		$msg->body     = $message;
		$msg->md5      = md5($message);
		// $msg->timeout = ??? @TODO

		try {
			$msg->save();
		} catch (Exception $e) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception($e->getMessage(), $e->getCode());
		}

		$options = array(
            'queue' => $queue,
            'data'  => $msg->toArray(),
		);

		$classname = $queue->getMessageClass();
		if (!class_exists($classname)) {
			require_once 'Zend/Loader.php';
			Zend_Loader::loadClass($classname);
		}
		return new $classname($options);
	}

	/**
	 * Get messages in the queue
	 *
	 * @param  integer    $maxMessages  Maximum number of messages to return
	 * @param  integer    $timeout      Visibility timeout for these messages
	 * @param  Zend_Queue $queue
	 * @return Zend_Queue_Message_Iterator
	 * @throws Zend_Queue_Exception - database error
	 */
	public function receive($maxMessages = null, $timeout = null, Zend_Queue $queue = null)
	{
		if ($maxMessages === null) {
			$maxMessages = 1;
		}
		if ($timeout === null) {
			$timeout = self::RECEIVE_TIMEOUT_DEFAULT;
		}
		if ($queue === null) {
			$queue = $this->_queue;
		}

		$msgs      = array();
		$info      = $this->_messageTable->info();
		$microtime = microtime(true); // cache microtime
		$db        = $this->_messageTable->getAdapter();

		// start transaction handling
		try {
			if ( $maxMessages > 0 ) { // ZF-7666 LIMIT 0 clause not included.
				$db->beginTransaction();

				$query = $db->select();
				if ($this->_options['options'][Zend_Db_Select::FOR_UPDATE]) {
					// turn on forUpdate
					$query->forUpdate();
				}
				$query->from($info['name'], array('*'))
				->where('queue_id=?', $this->getQueueId($queue->getName()))
				->where('handle IS NULL OR timeout+' . (int)$timeout . ' < ' . (int)$microtime)
				->limit($maxMessages);

				foreach ($db->fetchAll($query) as $data) {
					// setup our changes to the message
					$data['handle'] = md5(uniqid(rand(), true));

					$update = array(
                        'handle'  => $data['handle'],
                        'timeout' => $microtime,
					);

					// update the database
					$where   = array();
					$where[] = $db->quoteInto('message_id=?', $data['message_id']);
					$where[] = 'handle IS NULL OR timeout+' . (int)$timeout . ' < ' . (int)$microtime;

					$count = $db->update($info['name'], $update, $where);

					// we check count to make sure no other thread has gotten
					// the rows after our select, but before our update.
					if ($count > 0) {
						$msgs[] = $data;
					}
				}
				$db->commit();
			}
		} catch (Exception $e) {
			$db->rollBack();

			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception($e->getMessage(), $e->getCode());
		}

		$options = array(
            'queue'        => $queue,
            'data'         => $msgs,
            'messageClass' => $queue->getMessageClass(),
		);

		$classname = $queue->getMessageSetClass();
		if (!class_exists($classname)) {
			require_once 'Zend/Loader.php';
			Zend_Loader::loadClass($classname);
		}
		return new $classname($options);
	}

	/**
	 * Delete a message from the queue
	 *
	 * Returns true if the message is deleted, false if the deletion is
	 * unsuccessful.
	 *
	 * @param  Zend_Queue_Message $message
	 * @return boolean
	 * @throws Zend_Queue_Exception - database error
	 */
	public function deleteMessage(Zend_Queue_Message $message)
	{
		$db    = $this->_messageTable->getAdapter();
		$where = $db->quoteInto('handle=?', $message->handle);

		if ($this->_messageTable->delete($where)) {
			return true;
		}

		return false;
	}

	/********************************************************************
	 * Supporting functions
	 *********************************************************************/

	/**
	 * Return a list of queue capabilities functions
	 *
	 * $array['function name'] = true or false
	 * true is supported, false is not supported.
	 *
	 * @param  string $name
	 * @return array
	 */
	public function getCapabilities()
	{
		return array(
            'create'        => true,
            'delete'        => true,
            'send'          => true,
            'receive'       => true,
            'deleteMessage' => true,
            'getQueues'     => true,
            'count'         => true,
            'isExists'      => true,
		);
	}

	/********************************************************************
	 * Functions that are not part of the Zend_Queue_Adapter_Abstract
	 *********************************************************************/
	/**
	 * Get the queue ID
	 *
	 * Returns the queue's row identifier.
	 *
	 * @param  string       $name
	 * @return integer|null
	 * @throws Zend_Queue_Exception
	 */
	protected function getQueueId($name)
	{
		if (array_key_exists($name, $this->_queues)) {
			return $this->_queues[$name];
		}

		$query = $this->_queueTable->select();
		$query->from($this->_queueTable, array('queue_id'))
		->where('queue_name=?', $name);

		$queue = $this->_queueTable->fetchRow($query);

		if ($queue === null) {
			require_once 'Zend/Queue/Exception.php';
			throw new Zend_Queue_Exception('Queue does not exist: ' . $name);
		}

		$this->_queues[$name] = (int)$queue->queue_id;

		return $this->_queues[$name];
	}
}
